The present invention relates to a mobile communication unit such as e.g. a telephone for which a network has to be selected to which the unit is to be connected. The mobile communication unit, or particularly the telephone, comprises at least a first and a second mode of which one may be a manual mode and the other an automatic mode. Interaction means are provided through which interaction with the user is enabled and which is applied at some stages in a selection process.
The invention also relates to a method for connection of a mobile communication unit such as e.g. a telephone to a network. Still further the invention relates to a mobile communication system in which a number of mobile communication units are compatible with a number of networks within the system and in which the selection of network is done.
In an analogous way the invention also relates to a mobile communication unit which can be connected to systems of different standards or which can be used in different frequency bands.
Similarly the invention relates to a method of connecting a mobile communication unit wherein these options are available.
A number of network selection methods are known today but none of them is really satisfactory for a number of reasons.
Known GSM (Groupe Special Mobile) telephones can be set in two different network modes. One mode relates to an automatic search mode and the other is a manual search mode. If the automatic search mode is selected, the telephone is automatically changed to the network having the best conditions. If however the manual search mode is selected, connection is maintained to the network that was tuned to until the user actively changes the settings. Search mode is selected and set manually via for example a telephone network menu.
A problematic situation arises with a telephone of the above mentioned kind if the telephone is used in the vicinity of a border between two (or more) countries. If the conditions relating to the home network are not good, or not the best in relation to other accessible networks, the telephone is switched over to a foreign network if the automatic search mode was set. If a user is not used to this situation or is not aware of it, the situation arises that for example the home country can not be reached without a national code being dialled. This means that if for example a Swedish user makes telephone calls from his Swedish telephone when he is in the vicinity of the Danish border, he might have to call 0046 (the national code of Sweden) in order to reach Sweden and possibly he is not aware of this fact or he might not know of the national code etc. Moreover this situation may change frequently if he stays in the region of the border for some time since the best connection with the network varies making this situation even more complicated. Further still, if a Swedish subscriber, even when in Sweden, in a situation as discussed above, is connected to e.g. a Danish network the charges will be higher, since generally the charges of the home network are the least. This is very unsatisfactory to the subscribers.
Therefore it is frequent that the user sets the telephone in the manual search mode. However, this gives rise to complications when the user goes abroad since then he does not know how to change it. Such occurrences may consequently cause quite a lot of confusion to a user and may even restrict the use of mobile telephones both for a particular user and in more general terms.
Moreover, the situation may grow even more complicated in the future. In the GSM-system, which here is given merely as an example, it is presently not possible to roam between networks within one and the same country. This means that if for example there are two or more networks within one and the same country (operated by different operators), it is not possible to roam between these networks. It is only possible to roam between networks in different countries, thus it is possible to roam from a first network operated by a first operator in one country to another network operated via second operator in another country.
Generally an operator of a first country may have concluded an agreement with a specific operator in a second country so that when the second network, i.e. the network in the second country, can not be reached or has a bad quality or anything the like, the user may select and connect to a third network operated by still another operator in the second country if such can be reached, has a better quality, or for some other reason is more attractive.
However, it has been proposed for the new PCS-PCN standards, (for instance DCS 1800 which is an enhanced GSM system at 1800 MHz) that roaming be enabled between networks belonging to different operators within one and the same country as well.
In DCS 1800 the operator of a network to which a user subscribes, denoted the first network, may conclude an agreement with other operators of other networks (which of course have to be compatible) denoted second networks, according to which the user may select and connect to a second network if the first network is not reachable or has a bad quality or similar and if the second network is reachable or has a superior quality or similar.
However, the situation may arise that the best network according to some given standards is not the one preferred by the user for different reasons. One reason may be that one network is preferable because it is cheaper even if the quality is somewhat lower but still acceptable or the home network may be preferred if it still works although it does not at the moment have the same quality as some other network.
U.S. Pat. No. 5,261,117 relates to the selection of radio system when a system selected by the operator can not be found. The selection of an alternative system thus will take place automatically with the use a of priority list. Periodical attempts are done to return to the system selected by the operator. Moreover periodical attempts are done in order to connect to the highest possible system on the priority list. The user can also choose not to use the automatic searching. However, this system is quite complicated and it does not facilitate the use of the telephone for a user who for example is close to a border between countries so that the user easily can obtain knowledge about in which network he is and to control this. In another document, U.S. Pat. No. 5,159,625, it is stated that conventional cellular mobile telephones can use any of a number of different programable selection methods to select which cellular system to be used for communication. Whereas selection processes of this kind for example may consist of only selecting one system or that one system is preferred but if this is not accessible, another can be used etc. Furthermore, it is possible to only use the home system. Usually the telephone also comprises a default process which can be changed by a user. However, in practice the user will not do so to a great extent since it is too complicated. According to the document it is difficult for a user who is roaming to, in an appropriate way, select a foreign network. This document therefore gives a method according to which the telephone selects a set of frequencies to be used for communication. Furthermore the telephone stores a list of system identification numbers which gives the cellular systems not to communicate with. The telephone detects and displays while roaming and during roaming the telephone gets a system identification number relating to the system which can be used for communication. This foreign system is selected according to a system selection process and it communicates on a first frequency group. Then the telephone checks the system identification number of this foreign system with a list on numbers and if it is identified on the list, the telephone shall communicate on a second set of frequencies. Also this method is complicated and not user-friendly.
Dual mode telephones are known which can be connected to two different system standards (c.f. AMPS-D-AMPS; Advanced Mobile Phone System; Digital AMPS). Moreover, dual mode telephones are known which can connect to different frequency bands, c.f. TACS (Total Access Communication System). However, the similar objects and needs as discussed above in relation to network selection are also not fulfilled in any of these selection cases.